1. Field of the Invention
The present invention relates to a mask module, and more particularly to a dynamic mask module for generating dynamic mask patterns.
2. Description of the Related Art
During semiconductor fabrication, photolithography is an essential process. Usually, whether a technology is complicate can be determined by the number of the lithographic process and mask. A mask is made from transparent glass and a patterned Cr layer is formed thereon. When a light source is applied thereto, the mask pattern can be transferred to the photo-resist on the substrate.
For high resolution, uniformity of light, stability and quality of mask are key factors thereof. Traditionally, the mask patterns are taped out to the mask manufacturing companies for fabricating masks. The number of the mask depends on the complexity of the technology. The cost of mask depends on the resolution of line width; that is also the main reason that causes the high cost of mask.
For fabricating a semiconductor product, at least on mask is required depending on the complexity of the technology. Therefore, during the process loading and unloading masks increase process time. Additionally, an alignment step is required after a mask is changed, or misalignment of different layers occurs. Moreover, traditional gray-level mask uses special and expensive material for obtaining different exposure depths which is also a reason causing high cost of fabrication.
For example, in rapid prototyping (RP), physical application of the stereolithography printing process takes place via a commercial system known as a stereolithography apparatus (SLA), manufactured by 3D Systems, Inc., Valencia, Calif. It uses ultraviolet hardening resin via scanning mirror and takes a long time. In order to improve process time, solid ground curing (SGC) with ultraviolet is applied by using surface exposure. It includes: mask plotter cycle and mold growth cycle for reducing process time. The method comprises: receiving cross-sectional data, performing image process, forming covering plate and forming image by static reflection loading. Although SGC can improve the process time, the time for loading and unloading masks and alignment steps are still required.